Tampons are now widely used for absorbent purposes in the field of feminine hygiene. Currently, there are two basic types: digitally insertable tampons which are designed to be inserted directly by the user's own fingers; and applicator style tampons which are inserted with the aid of an applicator. Both types are usually made by folding or rolling a loosely associated rectangular strip of absorbent material into a blank and then compressing the blank into a cylindrical shaped product known as a pledget. The pledget may or may not contain a cover material, depending upon the manufacturer. A withdrawal string is attached to the pledget before the tampon is wrapped and packaged for sale. The applicator style tampons require an assembly step prior to being wrapped and packaged.
In both digital and applicator style tampons, it is desirable for the tampon to maintain its compressed shape up until its time of use. Furthermore, it is beneficial to compress the pledget to a uniform density so that it has a tendency to expand uniformly as it is being used. Any non-uniform expansion of the tampon could cause leakage which is unacceptable to the final user.
Different apparatuses for compressing absorbent material into tampons are known. U. S. Pat. Nos. 4,685,178; 4,498,218; 4,109,354; 3,271,502 and German patent Nos. 3,605,150 and 2,446,959 relate to various apparatuses used to compress the absorbent material into a desired form. In recent years, many manufacturers have employed a two stage compression technique known in the art as a "pointer-shaper" style compressor. This type of compressor incorporates the use of pointers to pretuck the material into a desired form followed by shapers which give the pledget its final form. One disadvantage of the "pointer-shaper" style compressor is that it involves a two stage operation which does not uniformly compress the product to a uniform density. A second disadvantage is that the two stage method requires complicated equipment which is more difficult to make changes to in order to accommodate different size pledgets. A third disadvantage is that the sequential action of the pointers and shapers results in slower cycle times and therefore a more costly product.
Now an apparatus has been developed which can compress material into a pledget using only one compression step and which is capable of forming a product having a uniform density.